Question

Which of the following is true for the determination of the rotational effect of the bearings?

(a) If we are considering the clockwise direction to be positive then the rotation along the counter clockwise direction is negative

(b) If we are considering the clockwise direction to be negative then the rotation along the counter clockwise direction is also negative as no such assumptions can be taken

(c) If we are considering the clockwise direction to be positive then the rotation along the counter clockwise direction is also positive as no such assumptions can be taken

(d) If we are considering the clockwise direction to be negative then the rotation along the counter clockwise direction is neither positive nor negative as we only pre assumed the clockwise direction

The question was posed to me during an interview for a job.

Query is from Frictional Forces on Journal Bearings topic in portion Friction of Engineering Mechanics

Answer 1

Correct option is (a) If we are considering the clockwise direction to be positive then the rotation along the counter clockwise direction is negative

For explanation I would say: We can take such assumptions. We are free to do so. We just need to specify if clockwise is positive then the counter clockwise is to be negative. Also such an assumption are very useful in the 2D calculation of the moments caused by various forces on the body.